In recent years, the saturated fatty acids have been castigated and maligned as contributing to arteriosclerosis and other coronary disease. However, most of the studies on saturated fatty acids have dealt with long chain triglycerides ("LCT"). Fatty acids, whether of animal, vegetable or marine origin, are normally associated with triglycerides as acyl side chains to a glycerine backbone. Fats and oils of animal, vegetable and marine origin are primarily LCT's, which have 14 or greater carbon atoms in the acyl chain, but can range from 4 to 24 carbon atoms.
It has been long known that the kernel oils are composed primarily of fatty acids which have 14 or less carbon atoms in the chain. Coconut oil and palm kernel oil are typical of these kernel oils and represent a class of fats distinct from conventional fats and oils. Approximately two-thirds of the fats in the kernel oils are saturated, and the majority of the fatty acids have 12 carbon atoms or fewer. Over the years, a number of kernel oils, primarily hydrogenated coconut oil, have been cited as atherogenic because of their high saturated fat content. The kernel oils have been considered poor for food and nutritional applications because of their association with saturated LCT's and stearines.
A recent development in fatty acid nutrition has been the acceptability of the medium chain triglycerides ("MCT") which are obtained, primarily, from fractionation of the kernel oils. MCT's are the first fraction out of three in the normal fractionation process. The MCT's are made up of about 1-2% C.sub.6, 65-75% C.sub.8, 25-35% C.sub.10 and 1-2% C.sub.12 fatty acids. For further details on fractionation, see "Medium-chain triglycerides: an update", A. C. Bach and V. K. Babayan, Am. J. Cl. Nut. 36:950-962 (1982).
The nutritional applications and the unique advantages of the MCT's have led to research in physical mixes of MCT's and LCT's as well as the formation of rearranged structured lipids. The structured lipids have MCT's and LCT's on the same triglyceride backbone and have been shown particularly effective for controlled triglyceride nutrition in hypercatabolic mammals. For example, see U.S. Pat. No. 4,528,197 to G. Blackburn.
The kernel oils themselves form naturally occurring structured lipids. Fraction 2 of these kernel oils, which constitutes approximately 50-65% of the total oil, has almost entirely C.sub.12 or lauric fats. The C.sub.12 fats are unique because they can be absorbed into the body by either the portal system or the lymphatic system. In contract, the MCT's are absorbed solely by the portal system while the LCT's are absorbed solely by the lymphatic system.
Structured lipids have an absorption pattern which depends on the molar ratios of the medium and long chain fatty acids on the glyceride molecule. The C.sub.12 fatty acids have the most versatile absorption pattern because of the dual transport mechanism.
Accordingly, an object of the invention is to provide a lipid source, primarily for use in a controlled diet for critically ill patients, which has lauric acid as the primary fatty acid.
Another object of the invention is to provide a lipid emulsion with lauric fats as the primary fatty acid source.
A further object of the invention is to provide a dietary supplement based on naturally occurring kernel oils which acts as a natural structured lipid.
These and other objects and features of the invention will be apparent from the following description and the claims.